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CCIE BGP

Bgp (Border Gateway Protocol) is one of the major topics in the exam and from my point of view the most complex one, as there are so many things that can be achieved with configuring BGP due to the flexibility of the protocol.In my quest of learning I also go trough documentation outside Cisco as it is important to get to know the protocol as it is and not only the Cisco point of view.So I came across with this fine PDF i am sure you will love it if you didn't already know about it before, it is a small reminder on the basics of BGP."Nice to see the number of bgp entries is almost 300000 this is an amazing jump in entries from 2001 also you have there some other interesting reports only for general knowledge"

Maximum routes under customer vrf, if the service provider had unlimited resources he would not have needed that!however normally resources are limited and expensive, and Service provider would like to make money from his available resources. maximum routes configured under VRF provide a mean of controlling PE local resource and abuse avoidance from the CE side.I have vrf called DC_EXTRANET, you can see that I have 16 routes, I have configured
10 maximum routes under that vrf however I did not want to be aggressive so I have set the
warning only option.
See that immediately I get a notice that I have more routes then the maximum, however no action
is taken other then alerting and sending a syslog.
!
PE_ashdod_otherisp.n(config-vrf)# maximum routes 10 warning-only
% The current number of routes in the routing table is equal to, or exceeds the configured warning limit
PE_ashdod_otherisp.n(config-vrf)#
*Nov 26 20:39:41.175: %IPRT-3-ROUTELIMITWARNING: IP routing table limit warning - DC_…

ISIS is simple to operate normally while everything is working, most common deployments are flat network based on L2, however when there is a problem and we need to start troubleshooting then people start to get lost.So I would like to provide some tools on how to read ISIS database.notice to the “*” sign, that mean LSP was generated on the router you did the show command, you can see that host name from the show command match also host name on the LSPID,LSPID identified by hostname.xx-yy, xx is normally 00 unless that LSP is pseudo node LSP generated by DIS , yy is representing the number of fragments for that LSP 00 – FF (max 255 fragments, plenty), most cases all the important information will be in 00 unless there are many fragments.LSP Holdtime is the amount of time an LSP will stay in database without any refresh.ATT/P/OL - 0/0/0, ATT bit or attached bit is used on L1/L2 connected to L1 node, if set to 1 L1 node will generate default route to the best L1/L2 node (best metric)AT…